Chest wall fractures, and in particular, fractures of rib bones of the rib cage, can cause potentially life-threatening respiratory insufficiencies, accounting for up to 50% of the mortality in thorax injuries. Fracture of a rib bone can occur at any location along the bone. However, the most critical fractures often involve multiple fracture of each of a set of adjacent rib bones. In particular, if four or more consecutive rib bones of the rib cage each sustain two or more fractures, for example, to create a column of bone fragments flanked by fractures sites, the fracture pattern is referred to as a flail chest injury. In flail chest injury, a fractured region of the chest wall is detached from the remainder of the chest wall, that is, no longer held in position by the rib cage. Accordingly, this fractured region can move independently of the chest wall during respiration, resulting, for example, in lung collapse.
Flail chest injury may be treated non-operatively or operatively to restore the anatomy and physiological function of the chest wall. Non-operative treatment generally involves aggressive pain control and mechanical ventilation. As a result, non-operative treatment has been associated with prolonged stays in the hospital and increased mortality rates. Operative treatment generally involves reducing and stabilizing rib fractures with internal fixation devices (osteosynthesis hardware), such as wires and/or bone plates. Bone plates are sturdy devices that are installed on the surface of bones, for example, by securing the bone plates to bone with bone screws. The bone plates generally are positioned to span fractures or other discontinuities in the bones and thus keep bone fragments aligned and stabilized during healing. In treatment of flail chest injuries, bone plates may be secured to multiply fractured ribs, to effectively re-unify the rib cage as the ribs heal.
Operative stabilization of flail chest injuries, such as with bone plates, can provide significant benefits over non-operative treatment. For example, operative stabilization can reduce the need for, and thus the mortality associated with, prolonged mechanical ventilation. In addition, operative stabilization can dramatically reduce pain during respiration, yield faster fracture healing, prevent persistent respiratory compromise, and reduce costs for treatment.
Despite the widely accepted benefits of operative stabilization to treat flail chest injury, it is difficult to provide bone plates configured specifically for installation on rib bones, due to the complex and varying surface geometry of the rib cage. Accordingly, generic bone plates have been used to fix rib bones. These generic plates, as provided, are straight and generally planar. These generic plates thus require substantial bending, generally intra-operatively by a surgeon, to custom-contour each plate according to a target surface region of a particular rib bone. This substantial intra-operative bending may be undesirable for many reasons. For example, this bending generally increases the time a patient spends in surgery, increasing the cost of surgery and the risk of surgical or post-surgical complications (such as infection). In addition, substantial bending may weaken the bone plate. Furthermore, if a generic bone plate is not conformed sufficiently to the rib surface, the bone plate may apply a concentrated stress to the rib bone, which may fracture the rib bone.